The present invention relates to methods of extracting anti-oxidant compositions from olives and the by-products of olive oil production. More specifically, the present invention provides simple and efficient methods of obtaining compositions rich in antioxidant compounds from fresh olives, from olive pulps produced as a by-product of olive oil manufacturing, from olive oil, and from wastewater from olive oil manufacturing. The invention also relates to antioxidant compositions and products containing the antioxidant compositions.
The Mediterranean diet, a diet rich in fresh fruits, vegetables and relatively low in animal fats, has long been considered exemplary of healthy diets. Part of the perceived health benefits of the Mediterranean diet has been attributed to the consumption of olive oil as the principal dietary fat. (See, e.g., Willett, W., Sacks, F., Trichopoulou, A., Drescher, G., Ferro-Luzzi, A., Helsing, E., Trichopoulos, D., xe2x80x9cMediterranean diet pyramid: a cultural model for healthy eatingxe2x80x9d, Am. J. Clin. Nutr., 1995; 61(suppl): 1402S-1406S.) Indeed, consumption of olive oil has been shown to be associated with a variety of health benefits, including a lower incidence of heart disease and a lower incidence of breast cancer. Visioli, F., Galli, C., xe2x80x9cNatural antioxidants and prevention of coronary heart disease: the potential role of olive oil and its minor constituentsxe2x80x9d, Nut. Metab. Cardiovasc. Dis., 1995; 5: 306-314, and Trichopoulou, A., Katsouyanni, K., Stuver, S., Tzala, L., Gnardellis, C., Rimm, E. and Trichopoulos, D., xe2x80x9cConsumption of Olive Oil and Specific Food Groups in Relation to Breast Cancer Risk in Greecexe2x80x9d, J. Nat. Cancer Inst., 1995; 87(2): 110-116. These findings have prompted considerable research into the composition of olive oil, and the nature of the components of olive oil responsible for the observed beneficial health effects.
Much of the benefit of olive oil consumption has been attributed to the presence of natural antioxidant compounds, several of which have been isolated. Among the antioxidant compounds that have been isolated from olive oil are various phenolic compounds, including hydroxytyrosol ((3,4-dihydroxyphenyl)ethanol), tyrosol (p-hydroxyphenylethanol), p-hydroxybenzoic acid, vanillic acid, caffeic acid, oleuropein and other phenolic compounds. The structures of several of these phenolic compounds are shown for reference. 
These compounds have shown in vitro biological activity, including inhibition of platelet aggregation (Petroni, A., Blasevich, M., Salami, M., Papini, N., Montedoro, G. F., Galli, C., xe2x80x9cInhibition of platelet aggregation and eicosanoid production by phenolic components of olive oilxe2x80x9d, Thrombosis Research, 1995; 78: 151-160), inhibition of LDL oxidation Visioli, F., Bellomo, G., Montedoro, G., Galli, C., xe2x80x9cLow density lipoprotein oxidation is inhibited in vitro by olive oil constituentsxe2x80x9d, Atherosclerosis, 1995; 117: 25-32), prevention of reactive oxygen metabolite (ROM)-induced cytotoxicity in human cell culture (Manna, C., Galletti, P., Cucciolla, V., Moltedo, O., Leone, A., Zappia, V., xe2x80x9cThe Protective Effect of the Olive Oil Polyphenol (3,4-Dihydroxyphenyl)ethanol Counteracts Reactive Oxygen Metabolite-Induced Cytotoxicity in Caco-2 Cellsxe2x80x9d, J. Nutr., 1997; 127: 286-292), inhibition of formation of thromboxane B2 (TxB2) (Petroni, A., Blasevich, M., Salami, M., Servili, M., Montedoro, G. F., Galli, C., xe2x80x9cA Phenolic Antioxidant Extracted from Olive Oil Inhibits Platlet Aggregation and Arachidonic Acid Metabolism in vitroxe2x80x9d, World Rev. Nutr. Diet, 1994; 75: 169-172), and inhibition of formation of leukotriene B4 (LTB4) (Petroni, A., Blasevich, M., Papini, N., Salami, M., Sala, A., Galli, C, Inhibition of leukocyte leukotriene B4 production by an olive oil-derived phenol identified by mass-spectrometryxe2x80x9d, Thrombosis Research, 1997; 87: 315-322). Thromboxane B2 and leukotriene B4 are two important substances secreted by polymorphonuclear leukocytes involved in pathophysiological processes related to chronic inflammation and vascular injury. In addition, phenolic compounds in olive oil have shown antibiotic activity with both antimicrobial (see, e.g., Juven, B., Henis,Y., xe2x80x9cStudies on the antimicrobial activity of olive phenolic compoundsxe2x80x9d, J. Appl. Bacteriol, 1970; 33: 721-732) and antifungal properties (Mahmoud, A. L., xe2x80x9cAntifungal action and antiaflatoxigenic properties of some essential oil constituentsxe2x80x9d, Lett. Appl. Microbiol., 1994; 19: 110-113). Moreover, animal studies have shown that LDL from olive oil-fed rodents is significantly more resistant to oxidation than control samples (Scaccini, C., Nardini, M., D""Aquino, M., Gentili, V., Di Felice, M., Tomassi, G., xe2x80x9cEffect of dietary oils on lipid peroxidation and on antioxidant parameters of rat plasma and lipoprotein fractionsxe2x80x9d, J. Lipid Res., 1992; 33: 627-633). Thus, in light of the increasing amount of evidence showing the potential health benefits of olive oil and components of olive oil, it would be desirable to have processes for extracting antioxidant components from olive oil.
Despite the need for olive-derived antioxidant compositions, the prior art does not provide simple and effective processes for producing such compositions. European Patent Application No. EP 0 811 678 A1 discloses a process for extracting antioxidants from olives, in which olives are crushed, vacuum dried, and pressed to form a cake. The cake is then extracted with a hot medium chain triglyceride or a C2 to C6 alkylene glycol at a pressure of at least 40 bar, to obtain an antioxidant-enriched extract. This method requires the use of a pressure-piston apparatus for extraction, lyophilization equipment and supplies for freeze-drying, and other equipment and chemicals that result in a relatively complex, expensive process. Moreover, this process uses fresh green or ripe olives, which can be expensive.
Olive oil production, which also uses fresh olives, produces as by-products a solid olive mass, often called xe2x80x9cpulpxe2x80x9d, and wastewater from a water-olive slurry conventionally used in olive oil manufacturing. These olive oil production by-products, are potentially rich in antioxidant compounds, but have not been effectively exploited, due to the impracticality of extracting usable amounts of antioxidant compounds using conventional technology. Indeed, although it has been reported that olive oil production wastewater is rich in phenolic antioxidant compounds (Visioli, F., Vinceri, F. F., Galli, C., xe2x80x9cWaste waters from olive oil production are rich in natural antioxidantsxe2x80x9d, Experientia, 1995; 51: 32-34), there still does not exist a simple and practical method of extracting such compounds from the wastewater. In addition, several inferior grades of olive oil now used in industrial (rather than culinary) applications, and therefore relatively inexpensive compared to culinary grade olive oil, offer potentially rich sources of antioxidant compounds. To date, however, these potential sources of beneficial antioxidants have not been effectively exploited.
Thus, there is a need for methods of obtaining antioxidant compositions from olives, olive oil and olive oil manufacturing by-products that do not suffer from the foregoing disadvantages.
It is an object of the invention to provide cheaper and more effective methods of extracting antioxidant compositions from olives.
It is another object of the invention to provide methods of extracting antioxidant compositions from olive oil.
It is another object of the invention to provide methods of using olive pulp by-products of olive oil manufacturing to produce antioxidant compositions.
It is another object of the invention to provide methods of using wastewater from olive oil manufacturing to produce antioxidant compositions.
It is another object of the invention to provide naturally-derived compositions rich in antioxidant components.
It is still another object of the invention to provide antioxidant compositions that can be used to impart antioxidant activity to, or enhance the antioxidant activity in, products such as cosmetics, topical antioxidant compositions, nutritional supplements, food products, oils or preservative compositions.
In accordance with these and other objects, the present invention provides methods of extracting antioxidant compositions from various olive-based starting materials, such as green olives, black olives, olive pulps, olive oil, and wastewater from olive oil manufacturing. The present invention further provides antioxidant compositions produced by the present methods, as well as methods of enhancing the antioxidant activity of a product.
In one embodiment, the present invention provides a method of preparing an antioxidant composition from an olive, an olive pulp, or an olive oil. The method includes the steps of extracting the starting material with a polar aqueous solvent to form an aqueous phase containing antioxidant components, passing the aqueous phase through a solid matrix to trap the antioxidant components on the matrix, and washing the matrix with a polar organic solvent to yield a solution of the antioxidant composition in the polar organic solvent. Optionally, the organic solvent can be partially removed to form a liquid concentrate, or further removed to leave a dry, solid antioxidant composition.
In another embodiment, the present invention provides a method of preparing an antioxidant composition from wastewater from olive oil manufacturing. The method includes the steps passing the wastewater containing antioxidant components through a solid matrix to trap the antioxidant components on the matrix, and washing the matrix with a polar organic solvent to yield a solution of the antioxidant composition in the polar organic solvent. Optionally, the organic solvent can be partially removed to form a liquid concentrate, or further removed to leave a dry, solid antioxidant composition.
In another embodiment, the present invention provides an antioxidant composition produced by any of the methods of the present invention.
In another embodiment, the present invention provides nutritional supplements having antioxidant activity and including an antioxidant composition produced by any of the methods of the present invention.
In another embodiment, the present invention provides a method of increasing the antioxidant activity of a product. The method includes the steps of obtaining an antioxidant composition from olives, olive pulp, olive oil, or wastewater from olive oil production, and combining the antioxidant composition with a product to enhance the antioxidant activity of the product.
These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.